Expectancy

Robert Rosenthal brought to public attention a powerful type of self-fulfilling prophecy, in a classic experiment about the expectations of teachers (Rosenthal & Jacobson, 1968). In the experiment, all the students in a class were given a standard IQ test. After the results were scored, the researchers informed the teachers that five students in the class had unusually high IQ scores and would probably be "spurters" who leaped ahead of their classmates during the remainder of the year. In reality, the five children were picked at random. By the end of the year, all the children had gained in IQ, but the five "spurters" had gained much more than other students. Evidently the teachers treated them differently after being told to expect sudden improvement.

What was the Pygmalion Effect?

This finding was dubbed the PygmalionEffect. In a Greek myth, a sculptor named Pygmalion fell in love with a statue of a beautiful woman that he had created. The statue then came to life. Similarly, teachers presented with a "beautiful image" of five students brought that image to life.

Where did Rosenthal's research begin? How did Rosenthal make student researchers into subjects?

Rosenthal (1994) said his line of research started when he almost ruined his doctoral dissertation research by accidentally biasing his research toward an outcome he expected. Instead of covering up his mistake, he was inspired by it. He began to study the phenomenon of experimenter bias. With K.L. Fode, Rosenthal did an experiment in which the true subjects were student researchers. The student researchers were instructed to have subjects rate photographs. Half the experimenters were led to expect high ratings, the other half were led to expect low ratings. Sure enough, the experimenters got the results they expected. "Experimenters expecting high ratings obtained substantially higher ratings than did experimenters expecting low ratings."

How did Rosenthal show experimenter bias in animal experiments?

Rosenthal and colleagues next tried an experiment with student researchers who were teaching rats to run through mazes. Half the student experimenters were told their rats had been specially bred for good performance. The other half were told they rats had been bred for poor performance. Once again, the student experimenters seemed to create the effects they expected. The bright rats (which were actually no different from the dull rats) performed much better at maze-running and other tests of rat intelligence.

What surprising finding did Rosenthal turn up, in his study of children in school?

At this point, Rosenthal and Jacobson realized they had discovered a powerful effect. They wondered if a similar effect might operate in schools. They did their famous study, later summarized in a book titled Pygmalion in the Classroom: Teacher expectation and pupils' intellectual development. (1968). Not only did teachers apparently give a boost to students who were expected to be high achievers: there was another, more disturbing finding.

A surprising finding was that the more children in the control group gained in IQ, the more unfavorably they were judged by their teachers. Apparently there were hazards to unpredicted intellectual growth. (Rosenthal, 1994, p.179, fn)

In other words, when students who were not expected to be "spurters" did exceptionally well, teachers seemed disappointed! Not all researchers agree with Rosenthal about this point, however. One study confirmed the Pygmalion effect when teachers had positive expectations but found that students who did unexpectedly well did not disappoint teachers, nor was their performance dragged down by negative expectations ("Study finds unexpected result on teachers' belief in students," 1997, November).

What were the important implications of this research?

Rosenthal's work had a major impact, because the effect he discovered seemed very important. If teacher expectations have a big impact, there might be all sorts of biasing effects in the school system. Early test scores and other sources of prejudice might keep some students down while encouraging others to leap ahead. Black or Hispanic children might be held back by the negative expectations of white teachers. Similarly, girls might be held back by negative expectations about their abilities in math or science. On a more positive note, perhaps any child could be made to act like a gifted student, simply by planting positive expectations in the minds of teachers.

f the mechanisms of the Pygmalion Effect discovered in the third decade of research?

Rosenthal and colleagues worked for many years to document the Pygmalion Effect in a variety of contexts. After two decades of research, there was little doubt that the effect occurred. At that point the researchers turned their attention to investigating the mechanisms of expectancy effects. How were they occurring? The third decade of research on expectancy effects revealed four main factors:

1) The emotional climate was affected by expectations. (Teachers acted warmer toward students they expected to do well.)

2) The behaviors of teachers were different. (Teachers gave the "spurters" more difficult material to study.)

3) The opportunities to speak out in class were different. (Teachers gave these students more opportunities to respond in class and more time to answer questions.)

4) The level of detailed feedback about performance was different. (Teachers gave these students more informative feedback.) [Adapted from Rosenthal, 1994]

What were the most important factors, in Rosenthal's opinion?

While all four factors were important, Rosenthal said, the effects of emotional climate and teacher behavior were most important. "Teachers appear to teach more and to teach it more warmly to students from whom they have more favorable expectations."

In what other social situations does the same sort of effect occur?

Rosenthal notes that the expectancy effect has been documented in business management (where the biasing effect is the expectations of employers about their employees), in courtrooms (where the biasing effect is the expectations about the defendant's guilt or innocence), and in nursing homes (where the biasing effect is the expectation that a patient will get better or worse). In all cases, the expectations tend to come true, whether they are based on any objective evidence or not. Apparently, as a general rule, people make their expectations come true. Rosenthal's research shows the Pygmalion effect is not only important; it is robust. It is a strong effect that occurs in many situations.